Adventurous male pup Hanno was born to first-time mum Lara on Sunday, June 10, and the more laid-back male pup Oakley was born to second-time mum Bailey on Saturday, June 23.

Lara and pup Hanno. Photo by ZSL Whipsnade Zoo

After giving birth at the UK’s largest zoo, ten-year-old Lara and 11-year-old Bailey have taken to motherhood swimmingly, and are already proving to be doting mums to the lively pups.

Team Leader Tim Savage is overjoyed at the new arrivals. He said: “The first pup was immediately so curious and adventurous, we decided to name him Hanno, after the fifth century oceanic explorer.

“At night he goes on little missions and explores the sea lion house!

“Lara’s always been the cheekiest member of the group, but she’s so attentive with Hanno, never letting him out of her sight.

Hanno. Photo by ZSL Whipsnade Zoo

“Every time Hanno tries to go near the water, she pulls him back.

“This isn’t Bailey’s first pup, so she’s much more confident and relaxed.

“She leaves Oakley to snooze while she goes off for a swim. They’ve both had a little splash in the pool, but neither of the pups are strong swimmers yet.

“Over the next month they will learn to dive, and practice holding their breath, and soon visitors will see them confidently swimming around the pool with their mums, and dad Dominic.”

Bailey and her pup Oakley. Photo by ZSL Whipsnade Zoo

Covered in fur, the pups will eventually grow to be over two metres long.

The new pups are a valuable addition to the colony of California sea lions at Whipsnade Zoo and the European conservation breeding programme for the species.

Originating from the rocky coastlines of the Pacific Ocean, all along the west coast of the USA, California sea lions (Zalophus californianus) live in large colonies, led by a dominant male and his harem of female mates.